Compare treatment with an immunoadsorbent column composed of protein a colvalently bound to a silica matrix (prosorba column) to a sham treatment procedure. Plasma will be passed through a system with or without an immunoadsorbent column and then returned to the same patient. The prosorba column treatment removes some immunoglobulin G and preferentially IGG containing circulating immune complexes which are believed to play a role in the immune pathology of rheumatoid arthritis.